A Global Map of Accessibility
I came across this interesting map— Travel Time to Major Cities—developed by the European Commission and the World Bank for use with the World Bank's 2009 World Development Report, Reshaping Economic Geography.
It shows "how accessible some parts of the world have become whilst other regions have remained isolated. Accessibility—whether it is to markets, schools, hospitals or water—is a precondition for the satisfaction of almost any economic need. As economies grow from low to high income, production becomes more concentrated spatially. Some places—cities, coastal areas, and connected countries—are favored by producers."